An anaphoric form is a form that stands for a referent which is °coreferential with another referent (an antecedent) in discourse.
The definition is from Haspelmath (2023: 52). Typical anaphoric forms are anaphoric pronouns. Alternatively, one might say that an anaphoric form is "a form which always receives its referential interpretation from another expression in the context."
anaphoric pronoun (CXN) = a pronoun that is used for active referents. Example: English unstressed he, she, they are examples of anaphoric pronouns. Anaphoric pronouns are most often, but not always, used when the referent is active because it has been previously referred to in the discourse. (Section 3.3.1)